Low melting-point solders, articles made thereby, and processes of making same

ABSTRACT

A composition includes a tin-containing solder with a melting temperature below about 150° C. The tin-containing solder includes indium, tin, and bismuth as alloy elements, and optionally contains a doping material and/or a second-phase dispersiod. A process includes blending the tin-containing solder under non-alloying conditions to achieve the discrete dispersion of the doping material. A process also includes blending the tin-containing solder with the particulate to achieve the discrete dispersion of the particulate. The composition is also combined with a microelectronic device to form a package. The composition is also combined with a microelectronic device and at least one I/O functionality to form a computing system.

TECHNICAL FIELD

Embodiments relate to solder for bonding microelectronic devices. In particular, an embodiment relates to a solder paste that includes in situ alloying components that form an alloy during reflow.

BACKGROUND INFORMATION

Where a microelectronic device is sensitive to conventional oven reflow temperatures, which are about 200° to 220° C., reflow of electrical bumps needs to occur at temperatures less than about 125° C. The operating temperature range of a microelectronic device, however, can be in the range from about 50° to about 80° C. Such a device requires the solder to have a higher liquidus temperature to reduce thermally accelerated solder joint reliability failure modes, such as creep and fatigue, that can occur at the ordinary operating temperature range of the device. Multiple solder bump reflows and burn-in testing can make solder joint failure and device failure more likely.

Conventional solders are susceptible to thermally accelerated solder joint reliability failures such as creep and fatigue. One board mounting process with conventional solders requires at least two solder bump reflows. They include a ball attach first reflow and a board attach second reflow.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to understand the manner in which embodiments are obtained, a more particular description of various embodiments briefly described above will be rendered by reference to the appended drawings. These drawings depict embodiments that are not necessarily drawn to scale and are not to be considered to be limiting in scope. Some embodiments will be described and explained with additional specificity and detail through the use of the accompanying drawings in which:

FIG. 1 is cross-section of a composition according to an embodiment;

FIG. 2 is a process flow depiction of a solder paste mixture according to an embodiment;

FIG. 3 is a cross-section of a chip package according to an embodiment;

FIG. 4 is a cross-section of a flip-chip package according to an embodiment;

FIG. 5 is a cross-section elevation of a wire-bond chip according to an embodiment;

FIG. 6 is a process flow diagram according to an embodiment; and

FIG. 7 is a depiction of a computing system according to an embodiment.

DETAILED DESCRIPTION

The following description includes terms, such as upper, lower, first, second, etc., that are used for descriptive purposes only and are not to be construed as limiting. The embodiments of a device or article described herein can be manufactured, used, or shipped in a number of positions and orientations. The terms “die” and “processor” generally refer to the physical object that is the basic workpiece that is transformed by various process operations into the desired integrated circuit device. A die is usually singulated from a wafer, and wafers may be made of semiconducting, non-semiconducting, or combinations of semiconducting and non-semiconducting materials.

A board is typically a resin-impregnated fiberglass structure that acts as a mounting substrate for the die. A board can be prepared with a bond pad, also referred to as a bond finger, that is flush with the board, or the bond pad can be set upon the board surface. As depicted in this disclosure, a bond pad is not limited to being flush or setting upon the surface only because it is illustrated as such, unless it is explicitly stated in the text.

Reference will now be made to the drawings wherein like structures may be provided with like reference designations. In order to show the structures of embodiments most clearly, the drawings included herein are diagrammatic representations of inventive articles. Thus, the actual appearance of the fabricated structures, for example in a photomicrograph, may appear different while still incorporating the essential structures of embodiments. Moreover, the drawings show only the structures necessary to understand the embodiments. Additional structures known in the art have not been included to maintain the clarity of the drawings.

FIG. 1 is cross-section of a composition 100 according to an embodiment. In an embodiment, the composition 100 includes a tin-containing solder 102. In an embodiment, the composition 100 includes a zinc-containing solder 102. The composition 100 has modifications in some embodiments, however, that make it a compound. In an embodiment, the solder 102 is a monophasic composition.

Various low melting-point solders are disclosed according to several embodiments. Table 1 provides a summary of example embodiment solders. TABLE 1 Low Melting-Point Solder Embodiment Examples Example Sn, % In, % Bi, % Zn, % 1 42-19  0-25 58-56 0 1A 19 25   56 0 1B 42 0  58 0 1C 29-32 11-15 57 0 2 48-20 52-48  0-32 0 2A 42-26 52-48 10-22 0 2B 36-32 51-49 14-18 0 3  0-19 33-25 67-56 0 3A  5-14 31-27 64-59 0 3B  8-11 30-28 62-61 0 4  0-20 67-48 33-32 0 4A  5-15 62-53 33-32 0 4B  8-12 59-56 33-32 0 5 48-46 52-54 0 0-2 5A 47 53   0 1 6 0 32-33 66-67 0-1 6A 0 32.5 66.5 1 7 0 33.4-52.2 66.3-47.4 0.3-0.4 7A 0 38-48 60-50 0.3-0.4 8 0 52.2-66.8 47.4-32.7 0.4-0.5 8A 0 58-60 45-37 0.4-0.5 9 0   66-66.8 32.7-34     0-0.5 9A 0 66.8 32.7 0.5

In an embodiment, an indium-tin-bismuth first solder 102 is prepared. In this embodiment, the indium-tin-bismuth first solder 102 includes indium as a major component. In an embodiment, the indium-tin-bismuth first solder 102 includes indium in a range of about 36% to about 63% indium. A tin component is present in a range from about 28% to about 48% tin. The bismuth is present in a range from about 2% to about 26%.

In an embodiment, the indium-tin-bismuth first solder 102 includes indium in a range of about 41% to about 58% indium, the tin component is present in a range from about 34% to about 42%, and the bismuth component is present in a range from about 7% to about 19%. In an embodiment, the first solder 102 includes indium in a range of about 46% to about 53% indium, the tin component is present in a range from about 37% to about 39%, and the bismuth component is present in a range from about 12% to about 14%. In an embodiment, the first solder 102 includes about 49% indium, about 38% tin, and about 13% bismuth.

In an embodiment, the indium-tin-bismuth first solder 102 is prepared with at least one doping material. The at least one doping material is added to give the indium-tin-bismuth first solder 102 selected properties. In an embodiment, the indium-tin-bismuth first solder 102 is doped with about 1% or less of the at least one doping material. In an embodiment, the indium-tin-bismuth first solder 102 is doped with about 0.5% or less of the at least one doping material. In an embodiment, the indium-tin-bismuth first solder 102 is doped with about 0.1% or less of the at least one doping material.

In an embodiment, the at least one doping material includes zinc. In an embodiment, the at least one doping material is selected from titanium, zirconium, hafnium, and combinations thereof. In an embodiment, the at least one doping material is selected from yttrium, ytterbium, lanthanum, praseodymium, and combinations thereof. In an embodiment, the at least one doping material is selected from nickel, palladium, platinum, and combinations thereof. In an embodiment, the at least one doping material is selected from cobalt, rhodium, iridium, and combinations thereof. In an embodiment, the at least one doping material is selected from magnesium, manganese, iron and combinations thereof. In an embodiment, the at least one doping material is selected from copper, silver, gold, and combinations thereof.

In an embodiment, the at least one doping material includes zinc alone. In an embodiment, the at least one doping material includes silver alone. In an embodiment, the at least one doping material includes copper alone. Where the at least one doping material is present, the above-given concentrations of the first solders are adjustable proportionally by recalculating the percentages.

In an embodiment, the at least one doping material includes any two of zinc, silver, or copper. In an embodiment, the at least one doping material includes zinc and silver. In an embodiment, the at least one doping material includes zinc and silver with zinc as the major doping material. In an embodiment, the at least one doping material includes zinc and silver with silver as the major doping material.

In an embodiment, the at least one doping material includes zinc and copper. In an embodiment, the at least one doping material includes zinc and copper with zinc as the major doping material. In an embodiment, the at least one doping material includes zinc and copper with copper as the major doping material.

In an embodiment, the at least one doping material includes silver and copper. In an embodiment, the at least one doping material includes silver and copper with silver as the major doping material. In an embodiment, the at least one doping material includes silver and copper silver with copper as the major doping material.

In an embodiment, the at least one doping material includes all three doping materials of silver, copper, and zinc. In an embodiment, the at least one doping material includes all three doping materials with zinc as the majority doping material. In an embodiment, the at least one doping material includes all three doping materials with zinc as the majority doping material, and copper as the minority doping material. In an embodiment, the at least one doping material includes all three doping materials with zinc as the majority doping material, and silver as the minority doping material.

In an embodiment, the at least one doping material includes all three doping materials with zinc as the plurality doping material and copper as the minority doping material. In an embodiment, the at least one doping material includes all three doping materials with zinc as the plurality doping material and silver as the minority doping material.

By review of this disclosure, it will become apparent to one of ordinary skill in the art that combinations of zinc, silver, and copper are also preparable as doping materials in the indium-tin-bismuth solders, wherein silver is the doping material with the greatest presence, and zinc and copper are alternatively present with one of them in a lowest concentration. Similarly, the majority or plurality doping material may be complemented by equal concentrations of the two minority doping materials.

In an embodiment, the at least one doping material is supplied to the composition 100 by providing an atomized doping material in a particle size from about 0.1 micrometer (μm) to about 100 μm. The atomized doping material is blended into the composition 100 by mechanical alloying. In an embodiment, the mechanical alloying describes the blending action, but the atomized doping material is not substantially alloyed, but it is interstitial in the matrix of the first solder 110.

FIG. 2 is a process flow depiction of a solder paste mixture according to an embodiment. The process flow is depicted against a temperature-versus-time graphic to illustrate the state of the solder paste during processing. According to a process embodiment, the graphic ordinate depicts a room temperature of 20° C., a first ramp temperature of about 100° C., a flux activation temperature of about 120° C., a solder in situ alloying temperature of about 140° C., and a cooled solder temperature of 20° C. The abscissa depicts process time in arbitrary units.

In an embodiment, a process unit 200 includes a substrate 210 and a solder paste brick 212. Within the solder paste brick 212 is a solder paste matrix 216, which includes a solder mixture. In an embodiment, the solder mixture includes any solder as set forth in this disclosure.

The solder paste brick 212 also includes a discrete dispersion of the doping material according to any of the embodiments set forth in this disclosure. The doping material 220 is depicted within the solder paste brick 212 as four discrete particles for the purposes of illustration.

During processing, the solder paste brick 212 is heated during a ramp-up stage from room temperature to about 100° C. During further heating, the solder paste flux begins to activate. According to an embodiment, the process unit 201 is depicted as relating to the temperature of about 100° C. At about this temperature, the flux in the solder paste brick 213 begins to activate. The solder paste brick 213 is arbitrarily depicted with softening corners during flux activation. The solder paste matrix 217 is changing chemically during this process as the flux is activating and the solder mixture begins to soften. According to an embodiment, the discrete dispersion of the doping material 221 is not changed to the same degree as the solder mixture.

According to an embodiment, the process unit 202 is depicted as relating to the temperatures from about 120° C. to about 140° C. during the heating portion of the reflow process. At about this temperature range, the flux in the solder paste brick 214 has activated and the solder mixture in the solder paste matrix 218 is melted. The solder paste brick 214 is depicted arbitrarily with a substantially rounded profile. Additionally, the doping material 222 is depicted as enlarging while intermingling within the solder matrix 218 during the in situ alloying of the doping material 221 into the solder mixture.

According to an embodiment, the process unit 203 is depicted as relating to the temperatures from about 140° C. to about 20° C. during cool-down of the unit. At about this temperature range, the flux in the solder bump 215 has been substantially driven from the matrix 219. The solder bump 215 is depicted arbitrarily with a substantially rounded profile. Additionally, the doping material is depicted as substantially dispersed and alloyed into the matrix 219.

In an embodiment, preparation of the solder paste brick 212 is carried out by a non-alloying blending of components of the solder paste matrix 216. In an embodiment, the blending process is carried out in a conventional kneading device.

In an embodiment, during blending of the composition of the solder mixture, the paste including flux, and the doping material, no significant mechanical or chemical alloying occurs between the solder mixture and the doping material.

As depicted in FIG. 2, after the doping material powder particles are discretely dispersed into the solder paste, the solder paste is printed via an automated stencil print process and takes the form of the brick 212. As set forth herein, flux in the solder paste reacts chemically at increasing temperatures to release acids that reduce metal-oxides that are present. As the temperature reaches and surpasses the liquidus temperature of the solder mixture, the powder particles of the doping material(s) in the solder paste liquefy and alloy in situ. As depicted with the process unit 202, the matrix 218 coalesces and takes the form of a hemisphere. Simultaneously, the matrix 218 reacts chemically with under-bump metallization in the substrate 210 to form a metallic bond. Additionally, the doping material powder diffuses into the molten solder, although the liquidus temperature of the doping material powder may not be reached. Upon cooling, the solder bump 215 solidifies at a temperature that is higher than the liquidus temperature of the tin-containing solder that is depicted as part of the solder paste brick 212.

According to an embodiment, were the solder bump 215 to be reheated, the in situ-formed solder alloy would liquefy at a higher temperature than it did upon its first reflow, due to a change in composition from the in situ alloying process.

Reference is again made to FIG. 1. Prior to the in situ alloying process, if it is used according to an embodiment, a particulate can be dispersion-filled into the solder 100.

In an embodiment, the first solder 102 includes a first particulate 104 that is dispersed within the matrix of the first solder 102. The first particulate 104 is a second-phase component in the solder 102 that adds selected properties to the alloy. In an embodiment, the particulate occupies a volume in the composition in a range from about 0.1% to about 50%.

In an embodiment, the first particulate 104 is an inorganic dielectric material such as an oxide. Various oxides can be used for the inorganic dielectric material, such as alumina, thoria, titania (whether rutile or anatase), urania, zirconia, ceria, and combinations thereof. In an embodiment, the first particulate 104 is a carbide material such as tungsten carbide. In an embodiment, the first particulate 104 is a carbon-based structure such as graphite, a Fullerene, and combinations thereof. In an embodiment, the first particulate 104 is an intermetallic dispersion material such as Cu₆Sn₅, Cu₃Sn, Ni₃Sn₄, or the like, other intermetallics, and combinations thereof. In an embodiment, the first particulate 104 is a silicide material that approaches the coefficient of thermal expansion (CTE) of silicon, such as titanium silicide. In an embodiment, the first particulate 104 is a material selected from at least two of the above-enumerated materials or the like. In an embodiment, the first particulate 104 is a material selected from at least three of the above-enumerated materials or the like. In an embodiment, the first particulate 104 is a material selected from at least four of the above-enumerated materials or the like. In an embodiment, the first particulate 104 is a material selected from all of the above-enumerated materials or the like.

In an embodiment, preparation of the first particulate 104 is carried out by milling the first particulate 104 to a size distribution that is submicron. In an embodiment, the first particulate 104 has a size distribution that is 100% passing about 100 nanometer (nm). Milling of the first particulate 104 can be carried out in a high-energy ball mill such as a Fritsch Pulverisette 7, made by Fritsch, GmbH of Rudolstadt, Germany, and which can be obtained from Gilson Co. of Worthington, Ohio. Other milling equipment can be obtained to obtain submicron, and about 100 nm particulates.

In an embodiment, the first particulate 104 is milled in a tungsten carbide (WC) environment such as in a planetary ball mill that includes WC grinding balls as well as a WC vial. In a non-limiting example, graphite is milled under about 300 kPa Argon atmosphere, to form a nanoporous structure of a Fullerene. In a non-limiting example, alumina (Al₂O₃) is milled under about 300 kPa Argon atmosphere, to form a 100% passing 100 nm distribution.

FIG. 1 also illustrates the presence of two particulates according to an embodiment. In an embodiment, the first particulate 104 is an inorganic dielectric, and a second particulate 106 is present in a second morphology such as a fiber or a shattered structure. In an embodiment, the second particulate 106 includes a Fullerene that has an elongated structure. In an embodiment, the particulate material is selected from at least two of the above-enumerated materials or the like. In an embodiment, the particulate material is selected from at least three of the above-enumerated materials or the like. In an embodiment, the particulate material is a material selected from at least four of the above-enumerated materials or the like. In an embodiment, the particulate material is a material selected from all of the above-enumerated materials or the like.

Although FIG. 1 illustrates the distribution of at least the first particulate 102 as discretely isolated in the matrix of the tin alloy 102, in an embodiment, the first particulate 104 is present as a reticulated structure. In an embodiment where the first particulate 104 is a Fullerene, it is similarly a reticulated structure that is dispersed in the matrix of the tin alloy 102, and therefore is substantially touching neighboring particulates.

After preparation of at least one particulate such as the first particulate 104, the first particulate 104 (and the second particulate 106 if present) is blended into the matrix of the solder 102. In an embodiment, blending of the particulate(s) is carried out according to known technique, such that agglomeration of the particulate(s) is minimized. Such techniques can include conventional mechanical alloying equipment.

Although the shapes for the first particulate 104 and the second particulate 106 are respectively depicted as round and irregular, these shapes are depicted to distinguish the two particulate types.

FIG. 1 also illustrates the presence of two particulates according to an embodiment. In an embodiment, the first particulate 104 is a second-phase dispersiod as set forth above, and the second particulate 106 is the doping material prior to in situ alloying as set forth above.

Reference is again made to FIG. 1. In an embodiment, a bismuth-tin-indium second solder 102 includes bismuth as a major component. In an embodiment, the bismuth-tin-indium second solder 102 includes bismuth in a range of about 42% to about 62% bismuth. The tin component is present in a range from about 19% to about 42% tin. The bismuth-tin-indium second solder 102 also includes indium. The indium is present in a range from about 7% to about 28%.

In an embodiment, the bismuth-tin-indium second solder 102 includes bismuth in a range from about 46% to about 57% bismuth, the tin component is present in a range from about 24% to about 38%, and the indium component is present in a range from about 11% to about 24%. In an embodiment, the bismuth-tin-indium second solder 102 includes bismuth in a range of about 52% to about 54% bismuth, the tin component is present in a range from about 29% to about 33%, and the indium component is present in a range from about 15% to about 19%. In an embodiment, the bismuth-tin-indium second solder 102 includes about 52% bismuth, about 31% tin, and about 17% indium.

In an embodiment, the bismuth-tin-indium second solder 102 is prepared with at least one doping material. The at least one doping material is added to give the bismuth-tin-indium second solder 102 selected properties. In an embodiment, the bismuth-tin-indium second solder 102 is doped with about 1% or less of the at least one doping material. In an embodiment, the bismuth-tin-indium second solder 102 is doped with about 0.5% or less of the at least one doping material. In an embodiment, the bismuth-tin-indium second solder 102 is doped with about 0.1% or less of the at least one doping material.

In an embodiment, the at least one doping material for the bismuth-tin-indium second solder 102 includes silver alone. In an embodiment, the at least one doping material includes antimony alone. In an embodiment, the at least one doping material includes copper alone. Where the at least one doping material is present, the above-given concentrations of the bismuth-tin-indium second solder 102 are adjustable proportionally by recalculating percentages.

In an embodiment, the at least one doping material includes any two of silver, antimony, or copper. In an embodiment, the at least one doping material includes silver and antimony. In an embodiment, the at least one doping material includes silver and antimony with silver as the major doping material. In an embodiment, the at least one doping material includes silver and antimony with antimony as the major doping material.

In an embodiment, the at least one doping material includes silver and copper. In an embodiment, the at least one doping material includes silver and copper with silver as the major doping material. In an embodiment, the at least one doping material includes silver and copper with copper as the major doping material.

In an embodiment, the at least one doping material includes antimony and copper. In an embodiment, the at least one doping material includes antimony and copper with antimony as the major doping material. In an embodiment, the at least one doping material includes antimony and copper antimony with copper as the major doping material.

In an embodiment, the at least one doping material includes all three above-mentioned doping materials. In an embodiment, the at least one doping material includes all three doping materials with silver as the majority doping material. In an embodiment, the at least one doping material includes all three doping materials with silver as the majority doping material, and copper as the minority doping material. In an embodiment, the at least one doping material includes all three doping materials with silver as the majority doping material, and antimony as the minority doping material.

In an embodiment, the at least one doping material includes all three doping materials with silver as the plurality doping material and copper as the minority doping material. In an embodiment, the at least one doping material includes all three doping materials with silver as the plurality doping material and antimony as the minority doping material.

By review of this disclosure, it will become apparent to one of ordinary skill in the art that combinations of silver, antimony, and copper are also preparable as doping materials in the bismuth-tin-indium solders, wherein antimony is the doping material with the greatest presence, and silver and copper are alternatively present with one of them in a lowest concentration. Similarly, the majority or plurality doping material may be complemented by equal concentrations of the two minority doping materials.

In an embodiment, the second solder 102 includes any first particulate 104 that is set forth in this disclosure. In an embodiment, the second solder 102 includes any combination of a first particulate 104 and a second particulate 106 that is set forth in this disclosure.

In an embodiment, the at least one doping material can be added prior to effecting the dispersion of the particulate if it is present. In an embodiment, the at least one doping material can be mechanically blended into the second solder 102 for in situ alloying as set forth and illustrated in FIG. 2. In an embodiment, neither the particulate nor the doping material is present in the second solder 102.

FIG. 3 is a cross-section of a chip package 300 according to an embodiment. The chip package 300 includes a die 320 with an active surface 322 and a backside surface 324. In an embodiment, the chip package 300 includes an interface subsystem 326 that is a solder according to any embodiment set forth in this disclosure.

The die 320 is connected to a thermal management device. In an embodiment, the thermal management device is an integrated heat spreader (IHS) 328 that is disposed above the backside surface 324 of the die 320. The interface subsystem 326, in the form of a thermal interface material (TIM) is disposed between the backside surface 324 of the die 320 and the IHS 328.

In an embodiment, the IHS 328 is attached to a mounting substrate 330 with a lip portion 332 of the IHS 328. In an embodiment, the mounting substrate 330 is a printed circuit board (PCB), such as a main board, a motherboard, a mezzanine board, an expansion card, or another mounting substrate with a specific application.

In an embodiment, the thermal management device is a heat sink without a lip structure, such as a simple planar heat sink. In an embodiment, the thermal management device includes a heat pipe configuration.

In an embodiment, the solder such as the solder 100 in FIG. 1 is the main structure of a series of electrical bumps 334. The electrical bumps 334 are composed of a solder according to any embodiment set forth in this disclosure. The electrical bumps 334 are each mounted on a series of bond pads 336. The electrical bumps 334 make contact with the active surface 322 of the die 320. By contrast, the interface subsystem 326 makes thermal contact with the backside surface 324 of the die 320. A bond-line thickness (BLT) 338 is depicted. The BLT 338 is the thickness of the interface subsystem 326. In an embodiment, the BLT 338 is in a range from about 100 Å to about 1,000 microns.

FIG. 4 is a cross-section of a flip-chip package 400 according to an embodiment. A die 440, and a substrate 442 onto which it is mounted, are further mated with a board 444. The die 440 is coupled to the substrate 442 by a plurality of first bumps, one of which is illustrated with the reference numeral 446. In an embodiment, the first bumps 446 are composed of a solder according to any embodiment set forth in this disclosure. The substrate 442 is coupled to the board 444 by a plurality of second bumps, one of which is illustrated with the reference numeral 448. In an embodiment, the second bumps 448 are composed of a solder according to any embodiment set forth in this disclosure.

FIG. 5 is a cross-section elevation of a wire-bond package 500 according to an embodiment. The wire-bond package 500 includes a die 550 including an active surface 552 and a backside surface 554. The die 550 is disposed on a mounting substrate 556, which in turn is disposed on a board 558. Electrical coupling of the die 550 to the board 558 is done through a via 560. The die 550 is first coupled to the mounting substrate 556 by a bond wire 562 that connects to a wire-bond pad 564, and that is also assisted by a wire-bonding ball 566. In an embodiment, the wire-bond pad 564 is reverse wire bonded to the die 550 by first attaching the bond wire 562 at the wire-bonding ball 566, and second attaching the bond wire 562 to the die 550.

In an embodiment, the via 560 is filled with an interconnect 568. In an embodiment, the via 560 is not filled, as depicted in FIG. 1, and the electrical path relies substantially upon a via liner 566.

FIG. 5 also depicts electrical coupling of the die 550 to the board 558. The die 550 is coupled to a bump 570, which in an embodiment, is at least partially disposed in the via 560. The bump 570 can be any electrical connection such as a solder ball. In an embodiment, an interconnect 568 is disposed in the via 560.

According to an embodiment, the vertical profile of the entire package is lower due to the bump 570 being at least partially embedded in the mounting substrate 556. In an embodiment, the board 558 is a motherboard, a mezzanine board, an expansion card, or others. In an embodiment, the board 558 is a penultimate casing for a wireless handheld such as a wireless telephone.

It can be appreciated that any one or more of the interconnect 564, the wire-bonding ball 566, and the bump 570 is a solder according to any of the solder embodiments set forth in this disclosure.

FIG. 6 is a process flow diagram 600 according to an embodiment.

At 610, the process includes providing a solder according to any of the embodiments set forth in this disclosure. In an embodiment, the process flow terminates at 610.

At 620, a process further includes blending the solder with a doping material. By way of non-limiting example the first solder 102 or the second solder 102 is blended with any of the doping materials set forth in this disclosure. In an embodiment, blending includes pre-alloying. In an embodiment, blending includes non-alloying blending to achieve a discrete presence of the doping material until further processing such as by in situ alloying. In an embodiment, the process flow terminates at 620. In an embodiment, the process flow originates and terminates at 620.

At 630, the process flow includes blending the solder with a second-phase particulate. By way of non-limiting example, the second-phase particulate is the first particulate 104 and/or the second particulate 106 according to any of the embodiments set forth in this disclosure. In an embodiment, the process flow terminates at 630. In an embodiment, the process flow originates and terminates at 630.

In an embodiment the process flow includes both process 620 and 630.

At 640, the process flow includes printing the solder on a substrate. By way of non-limiting example, the interface subsystem 326 in FIG. 3 is printed on the substrate, being the die 320 or the IHS 328. In an embodiment, the process flow terminates at 640. In an embodiment, the process flow originates and terminates at 640.

At 642, the process flow includes assembling a mounting substrate with a die. By way of non-limiting example, the die 440 in FIG. 4, the die 440 and the substrate 442 are assembled. Further by way of non-limiting example, the die 440 and the board 444 are assembled as illustrated. In an embodiment, the process flow terminates at 642. In an embodiment, the process flow originates and terminates at 642.

At 650, the solder is reflowed. By way of non-limiting example, the wire-bonding ball 566 in FIG. 5 is reflowed during wirebonding thereof. Further by way of non-limiting example, the bump 568 is reflowed. Further by way of non-limiting example, where the solder is blended but not pre-alloyed with the doping material, the doping material alloys in situ with the solder. In an embodiment, the process flow terminates at 650. In an embodiment, the process flow originates and terminates at 650.

At 660, the process flow includes cooling the solder.

FIG. 7 is a depiction of a computing system according to an embodiment. The computing system 700 includes a solder bump and/or an interface subsystem such as any of the solders set forth in this disclosure. Hereinafter, where the computing system 700 refers to a microelectronic device that is coupled to a solder, it is understood to include any of the solders set forth in this disclosure. One or more of the foregoing embodiments of the solder may be utilized in a computing system, such as a computing system 700 of FIG. 7. Similarly, the computing system can include a die, a solder, a solder TIM, and a heat sink according to any of the article embodiments set forth in this disclosure.

In an embodiment, the computing system 700 includes at least one processor which is enclosed in a package 710, a data storage system 712, at least one input device such as keyboard 714, and at least one output device such as monitor 716, for example. The computing system 700 includes a processor that processes data signals, and may include, for example, a microprocessor, available from Intel Corporation. In addition to the keyboard 714, the computing system 700 can include another user input device such as a mouse 718, for example. Similarly depending upon the complexity and type of system, the computing system 700 can include a board 720 for mounting at least one of the microelectronic device package 710, the data storage system 712, or other components.

For purposes of this disclosure, a computing system 700 embodying components in accordance with the claimed subject matter may include any system that utilizes a microelectronic device system, which may include for example, a solder embodiment that is coupled to data storage such as dynamic random access memory (DRAM), polymer memory, flash memory, and phase-change memory. In this embodiment, the solder embodiment is coupled to any combination of these functionalities by being coupled to an input-output device. In an embodiment, however, the solder embodiment set forth in this disclosure is coupled to any of these functionalities. For an example embodiment, data storage includes an embedded DRAM cache on a substrate that is coupled to a solder embodiment. Additionally in an embodiment, the solder embodiment is part of the system with a solder embodiment that is coupled to the data storage of the DRAM cache. Additionally in an embodiment, a solder embodiment is coupled to the data storage 712.

In an embodiment, the computing system 700 can also include a solder embodiment that is coupled to a digital signal processor (DSP), a micro controller, an application specific integrated circuit (ASIC), or a microprocessor. In this embodiment, the solder embodiment is coupled to any combination of these functionalities by being coupled to a motherboard or the like. For an example embodiment, a DSP is part of a chipset that may include a stand-alone die processor (in package 710) and the DSP as separate parts of the chipset. In this embodiment, a solder embodiment is coupled to the DSP, and a separate solder embodiment may be present that is coupled to the processor in package 710. Additionally in an embodiment, a solder embodiment is coupled to a DSP that is mounted on the same board 720 as the package 710.

It can now be appreciated that embodiments set forth in this disclosure can be applied to devices and apparatuses other than a traditional computer. For example, a die can be packaged with an embodiment of the solder embodiment, and placed in a portable device such as a wireless communicator or a hand-held device such as a personal data assistant and the like. Another example is a solder embodiment that can be packaged as an embodiment and placed in a vehicle such as an automobile, a locomotive, a watercraft, an aircraft, or a spacecraft.

The Abstract is provided to comply with 37 C.F.R. §1.72(b) requiring an Abstract that will allow the reader to quickly ascertain the nature and gist of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims.

In the foregoing Detailed Description, various features are grouped together in a single embodiment for the purpose of streamlining the disclosure. This method of disclosure is not to be interpreted as reflecting an intention that the claimed embodiments of the invention require more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive subject matter lies in less than all features of a single disclosed embodiment. Thus the following claims are hereby incorporated into the Detailed Description, with each claim standing on its own as a separate preferred embodiment.

It will be readily understood to those skilled in the art that various other changes in the details, material, and arrangements of the parts and method stages which have been described and illustrated in order to explain the nature of this invention may be made without departing from the principles and scope of the invention as expressed in the subjoined claims. 

1. A composition comprising: indium in a range from about 36% to about 63%; tin in a range from about 28% to about 48%; and bismuth in a range from about 2% to about 26%.
 2. The composition of claim 1, wherein the composition includes a solder including: indium in a range of about 41% to about 58%; tin in a range from about 34% to about 42%; and bismuth in a range from about 7% to about 19%.
 3. The composition of claim 1, wherein the composition includes a solder including: indium in a range from about 46% to about 53%; tin in a range from about 37% to about 39%; and bismuth in a range from about 12% to about 14%.
 4. The composition of claim 1, wherein the composition includes a solder including: about 49% indium; about 38% tin; and about 13% bismuth.
 5. The composition of claim 1, further including: at least one doping material selected from zinc, titanium, zirconium, hafnium, yttrium, ytterbium, lanthanum, praseodymium, nickel, palladium, platinum, cobalt, rhodium, iridium, magnesium, manganese, iron, copper, silver, gold, and combinations thereof.
 6. The composition of claim 1, further including a zinc doping material in a concentration range from about 0.1% to about 1%.
 7. The composition of claim 1, further including doping materials of at least two selected from zinc, silver, and copper, wherein the doping materials are present in a combined concentration range from about 0.1% to about 1%.
 8. The composition of claim 1, further including: a particulate dispersed in the composition, wherein the solder provides a matrix for the particulate, and wherein the particulate has a size in a range below about 100 nm.
 9. The composition of claim 1, further including: a particulate dispersed in the composition, wherein the solder provides a matrix for the particulate, wherein the particulate has a size in a range below about 100 nm, and wherein the particulate occupies a volume in the composition in a range from about 0.1% to about 50%.
 10. The composition of claim 1, further including: a particulate dispersed in the composition, wherein the solder provides a matrix for the particulate, wherein the particulate has a size in a range below about 100 nm; and wherein the particulate is selected from an oxide, a carbide, a nitride, an oxynitride, a silicide, a carbon Fullerene, and combinations thereof.
 11. The composition of claim 1, further including: at least one doping material selected from zinc, titanium, yttrium, ytterbium, zirconium, nickel, cobalt, lanthanum, magnesium, manganese, iron, copper, silver, gold, palladium, praseodymium, and combinations thereof; and a particulate dispersed in the composition, wherein the solder provides a matrix for the particulate, wherein the particulate has a size in a range below about 100 nm, and wherein the particulate occupies a volume in the composition in a range from about 0.1% to about 50%.
 12. A composition comprising: bismuth in a range from about 42% to about 62%; tin in a range from about 19% to about 42%; and indium in a range from about 7% to about 28%.
 13. The composition of claim 12, wherein the composition includes a solder including: bismuth in a range from about 46% to about 57%; tin in a range from about 24% to about 38%; and indium in a range from about 11% to about 24%.
 14. The composition of claim 12, wherein the composition includes a solder including: bismuth in a range from about 52% to about 54%; tin in a range from about 29% to about 33%; and indium in a range from about 15% to about 19%.
 15. The composition of claim 12, wherein the composition includes a solder including: about 52% bismuth; about 31% tin; and about 17% indium.
 16. The composition of claim 12, further including: at least one doping material selected from zinc, titanium, zirconium, hafnium, yttrium, ytterbium, lanthanum, praseodymium, nickel, palladium, platinum, cobalt, rhodium, iridium, magnesium, manganese, iron, copper, silver, gold, and combinations thereof.
 17. The composition of claim 12, further including a zinc doping material in a concentration range from about 0.1% to about 1%.
 18. The composition of claim 12, further including doping materials of at least two selected from zinc, silver, antimony, and copper, wherein the doping materials are present in a combined concentration range from about 0.1% to about 1%.
 19. The composition of claim 12, further including: a particulate dispersed in the composition, wherein the solder provides a matrix for the particulate, and wherein the particulate has a size in a range below about 100 nm.
 20. The composition of claim 12, further including: a particulate dispersed in the composition, wherein the solder provides a matrix for the particulate, wherein the particulate has a size in a range below about 100 nm, and wherein the particulate occupies a volume in the composition in a range from about 0.1% to about 50%.
 21. The composition of claim 12, further including: a particulate dispersed in the composition, wherein the solder provides a matrix for the particulate, wherein the particulate has a size in a range below about 100 nm; and wherein the particulate is selected from an oxide, a carbide, a nitride, an oxynitride, a silicide, a carbon Fullerene, and combinations thereof.
 22. The composition of claim 12, further including: at least one doping material selected from zinc, titanium, yttrium, ytterbium, zirconium, nickel, cobalt, lanthanum, magnesium, manganese, iron, copper, silver, gold, palladium, praseodymium, and combinations thereof; and a particulate dispersed in the composition, wherein the composition provides a matrix for the particulate, wherein the particulate has a size in a range below about 100 nm, and wherein the particulate occupies a volume in the composition in a range from about 0.1% to about 50%.
 23. A composition comprising: from about 33% to about 67% indium; from about 32% to about 67% bismuth; and from about 0% to about 20% tin.
 24. The composition of claim 23, wherein the composition includes a solder including: indium in a range of about 25% to about 33%; tin in a range from about 0% to about 19%; and bismuth in a range from about 56% to about 67%.
 25. The composition of claim 23, wherein the composition includes a solder including: indium in a range from about 48% to about 67%; tin in a range from about 0% to about 20%; and bismuth in a range from about 32% to about 33%.
 26. A composition comprising: from about 52% to about 54% indium; from about 0% to about 2% zinc; and from about 46% to about 48% tin.
 27. The composition of claim 26, wherein the composition includes a solder including: indium in a range of about 52.5% to about 53.5%; zinc in a range from about 0.5% to about 1.5%; and tin in a range from about 46.5% to about 47.5%.
 28. The composition of claim 26, wherein the composition includes a solder including: about 53% indium; about 1% zinc; and about 47% tin.
 29. A composition comprising: from about 33% to about 67% indium; from about 32% to about 67% bismuth; and from about 0.1% to about 1% zinc.
 30. The composition of claim 29, wherein the composition includes a solder including: from about 32% to about 33% indium; from about 66% to about 67% bismuth; and from about 0.1% to about 1% zinc.
 31. The composition of claim 29, wherein the composition includes a solder including: from about 33.4% to about 52.2% indium; from about 47.4% to about 66.3% bismuth; and from about 0.3% to about 0.4% zinc.
 32. The composition of claim 29, wherein the composition includes a solder including: from about 52.2% to about 66.8% indium; from about 32.7% to about 47.4% bismuth; and from about 0.4% to about 0.5% zinc.
 33. The composition of claim 29, wherein the composition includes a solder including: from about 66% to about 66.8% indium; from about 32.7% to about 34% bismuth; and from about 0.1% to about 0.5% zinc.
 34. A package comprising: a substrate; a solder composition, selected from: a first solder including: indium in a range from about 36% to about 63%; tin in a range from about 28% to about 48%; and bismuth in a range from about 2% to about 26; and the solution, mixture, and reaction products of the first solder; or a second solder including: bismuth in a range from about 42% to about 62%; tin in a range from about 19% to about 42%; indium in a range from about 7% to about 28%; and the solution, mixture, and reaction products of the first solder; and a microelectronic device disposed on the substrate, wherein the microelectronic device is coupled to the solder.
 35. The package of claim 34, wherein the microelectronic device is a flip-chip die, and wherein the solder is selected from a thermal interface subsystem, an electrical bump, and combinations thereof.
 36. The package of claim 34, wherein the microelectronic device is a flip-chip die, and wherein the solder is selected from a first electrical bump that contacts a die, a second electrical bump that contacts a board and that is coupled to the die, and combinations thereof.
 37. The package of claim 34, wherein the microelectronic device is a wire-bond die, and wherein the solder is selected from a wire-bonding ball, an interconnect, a bump to a board, and combinations thereof.
 38. A computing system comprising: a substrate; a solder composition, selected from: a first solder including: indium in a range from about 36% to about 63%; tin in a range from about 28% to about 48%; bismuth in a range from about 2% to about 26%; and the solution, mixture, and reaction products of the first solder; or a second solder including: bismuth in a range from about 42% to about 62%; tin in a range from about 19% to about 42%; indium in a range from about 7% to about 28%; and the solution, mixture, and reaction products of the first solder; a microelectronic device disposed on the substrate; and at least one of an input device and an output device coupled to the microelectronic device, wherein the solder is coupled to the microelectronic device.
 39. The computing system of claim 38, wherein the computing system is disposed in one of a computer, a wireless communicator, a hand-held device, an automobile, a locomotive, an aircraft, a watercraft, and a spacecraft.
 40. The computing system of claim 38, wherein the microelectronic die is selected from a data storage device, a digital signal processor, a micro controller, an application specific integrated circuit, and a microprocessor.
 41. A process comprising: assembling a solder with a structure, the solder including: indium in a range from about 36% to about 63%; tin in a range from about 28% to about 48%; and bismuth in a range from about 2% to about 26%.
 42. The process of claim 41, before assembling, the process further including blending the solder with at least one of a second-phase particulate and a doping material.
 43. The process of claim 41, wherein blending the second-phase particulate includes first milling the second-phase particulate to a particle size about 100% passing 100 nm, followed by second kneading the second-phase particulate into the solder.
 44. The process of claim 41, wherein blending the second-phase particulate includes first kneading the second-phase particulate into the solder.
 45. The process of claim 41, before assembling, the process further including: blending the solder with a doping material; and wherein assembling the solder with a structure includes in situ alloying of the doping material during reflow of the solder against the structure, wherein the structure is selected from a heat sink, a die, a bump, a wire-bond pad, and combinations thereof.
 46. A process comprising: assembling the solder with a structure, the solder including: indium in a range from about 69% to about 97%; tin in a range from about 28% to about 48%; and bismuth in a range from about 2% to about 26%.
 47. The process of claim 46, before assembling, the process further including blending the solder with at least one of a second-phase particulate and a doping material.
 48. The process of claim 46, wherein blending the second-phase particulate includes first milling the second-phase particulate to a particle size about 100% passing 100 nm, followed by second kneading the second-phase particulate into the solder.
 49. The process of claim 46, wherein blending the second-phase particulate includes first kneading the second-phase particulate into the solder.
 50. The process of claim 46, before assembling, the process further including: blending the solder with a doping material; and wherein assembling the solder with a structure includes in situ alloying of the doping material during reflow of the solder against the structure, wherein the structure is selected from a heat sink, a die, a bump, a wire-bond pad, and combinations thereof. 